Need help with 19mth old

Hello! I have a 19mth old son who has always been a bad sleeper but has recently been getting worse. He goes to bed with no problems at all at 8pm but it never fails that he will wake up around midnight screaming and will not go back to sleep unless we put him in our bed ( which I dont like to do). I wake up at 430am to go to work so this is killing me and he is awful to sleep with so I dont get a good sleep once he is in bed with us. We tried CIO but he just climbs out of his crib so I cant do that and I was looking at cribtents but they are too expensive. Can someone offer some suggestions?